This invention is directed to an improved circuit for providing the fixed reference voltage with a minimum of power consumption, and in particular, to a circuit for providing a fixed reference voltage particularly suited for use in smallsized battery operated electronic instrumentation such as an analog-to-digital voltage tester.
Small sized battery operated electronic instruments, such as digital voltage testers utilize a Zener diade as a fixed reference voltage element. Although Zener diodes are particularly suited for use in miniaturized circuits requiring a fixed reference voltage, if the Zener diode continues to be energized, the power consumption thereof is considerable. It is noted that the greater the power consumption of the circuit elements in portable miniaturized electronic instruments, the faster the life of the batteries utilized to energize same will be exhausted. Moreover, when electronic instruments such as digital display voltage testers utilize LED (light-emitting diodes), fluorescent display tubes, etc. as the display elements, the power consumption is further increased. Although the use of liquid crystal display elements can considerably reduce the power consumption of the digital display, it is desired to substantially reduce the power consumption of the Zener diode, when same is utilized as a fixed reference voltage element.